1. Technical Field
The present disclosure relates to a package having a shield case, and more particularly to a package in which one surface of a substrate on which an electronic component is mounted is covered by a metallic shield case.
2. Background Art
In a package having a shield case, one surface of a substrate on which an electronic component is mounted is covered by a metallic shield case, and the package as shown in FIG. 4 is proposed in, for example, Japanese Unexamined Patent Publication: No. 10-284935.
In the package as shown in FIG. 4, each of the pawl parts 104, 104, . . . is formed in a lower end side of a metallic shield case 102 for covering one surface of a substrate 100 and is fitted into a corresponding recess 106 of recesses 106, 106, . . . formed in side surfaces of the substrate 100.
In the package as shown in FIG. 4, the pawl part 104 of the shield case 102 for covering electronic components 108, 108, . . . such as semiconductor elements mounted on the one surface of the substrate 100 are fitted into the recess 106 formed in the side surface of the substrate 100 and also is soldered on a plated layer 110 formed on a wall surface of the recess 106 by solder 112 as shown in a cross-sectional view of FIG. 5.
In addition, solder balls 114, 114, . . . serving as a plurality of external connection terminals are formed on another surface of the substrate 100.
The package shown in FIGS. 4 and 5 can be preferably used in a package in which a high-frequency component as an electronic component is mounted on one surface of a substrate.
However, in the conventional package having the shield case, as shown in FIG. 6, it is necessary to use the substrate 100 in which the recesses 106, 106, . . . are formed in the side surfaces. Thus, it is difficult to seal the electronic components 108, 108, . . . mounted on the one surface of the substrate 100 using a resin.
Namely, in the case of industrially manufacturing the substrate 100 shown in FIG. 6, as shown in FIG. 7, after forming a large-size original substrate 200 in which a plurality of substrates 100, 100, . . . are formed, elliptic through holes 202, 202, . . . are formed in parts of large-size original substrate 200 where the recesses 106, 106, . . . are formed, and then the plated layer 110 is formed on inner wall surfaces of the elliptic through holes 202, 202, . . . using electroless plating etc.
Next, after various electronic components are mounted on a region surrounded by the elliptic through holes 202, 202, . . . , the original substrate 200 is cut according to lines 204, 204, . . . passing through the centers of the elliptic through holes 202, 202, . . . and thus the substrate 100 shown in FIG. 6 can be obtained.
Thereafter, the shield case 102 is attached to the substrate 100 and the corresponding pawl parts 104 formed in the lower end side of the shield case 102 are fitted into each of the recesses 106, 106, . . . formed in the side surfaces of the substrate 100 and then the pawl parts 104 are soldered.
In this case, when the electronic components 108, 108, . . . are sealed with a resin after the electronic components 108, 108, . . . are mounted on the one surface of the substrate 100 in which the elliptic through holes 202, 202, . . . are formed, there is a possibility that the sealing resin penetrates into the elliptic through holes 202 and thus the pawl parts 104 of the shield case 102 cannot be fitted.
Therefore, the electronic components 108, 108, . . . mounted on the one surface of the substrate 100 are not sealed with the resin. In this case, in order to prevent contact between the metallic shield case 102 and the electronic components 108, 108, . . . , it is necessary to always ensure a space between the shield case 102 and the electronic components 108, 108, . . . and thus there is a limit to a request for downsizing of the package.
Further, a bonding wire that can cause contact with the shield case 102 cannot be used in electrical connection between the electronic components 108 and the substrate 100, and only a flip chip bonding can be used. Thus, it is requested that a bonding wire be used in electrical connection between the electronic components 108 and the substrate 100 even for the package having the shield case.